There is a short message reminder after changing the calling card.

This should be to turn on the function of retrieving the mobile phone and set the specified mobile phone number. You can enter the cloud service, get your phone back, turn off this function or delete the specified number.

If your mobile phone is lost or stolen, it is recommended to call the police as soon as possible.

At the same time, OPPO also provides you with basic location services, but this requires you to bind the OPPO account on your mobile phone and turn on the function of retrieving your mobile phone. Then you can visit and log in to the OPPO cloud service website through your computer, and log in to the OPPO account to locate and lock your mobile phone, so as to help you find your mobile phone to the greatest extent.

In this case, you turn on the phone search function, turn on the cloud service program and turn off the phone search function. If you have any other questions, you can enter the OPPO enterprise platform to ask the customer service.

That's because your mobile phone number is stored in the OPPO phone, not the mobile phone card. You can first put the mobile phone card back to the OPPO phone, transfer all the numbers to the mobile phone card on the OPPO phone, and then change the card to your C6.